a Genus of Dipterous Insects. 309 
(* rostgelb" in the description, “ferrugineis” in the specific character given by 
" Wiedemann), and that not only the posterior but all the tibiz are pitchy- 
black (* pechschwarz") with the anterior femora clavate and the tibize somewhat 
arched : Wiedemann, however, has been careless enough to omit the colour of 
the spines of the thorax in the specimen which he examined from Africa. As it 
is evident that Fabricius entirely disregarded the Linnean description, in which 
the scutellar spines are mentioned as “flav,” but described these spines as 
either red or black, varying, probably, according to sex, it would seem that 
he did not introduce the rufous colour of these spines from the Linnzan de- 
scription, but from an actual examination; and as such a variation is clearly 
not sexual, it appears to me that he confounded two distinct species with clear 
wings, and consequently both different from the Linnzean species, under the 
name of the latter. Moreover, as Wiedemann has not noticed the colour of 
the spines in the African species, we may perhaps consider that they are of 
the general colour assigned to the insect, namely, piceous ; in which case, the 
variety described by Fabricius with red spines would in all probability be the 
insect from Sumatra, and consequently a species distinct from any described 
in this memoir. 
Sectio IV. Alæ fasciis integris. 
Species 19. Dropsis Datmanni. Wied. 
Tas. IX. Fig. 17. 
Ferruginosa, alis fuscatis limpido fasciatis. 
Long. corp.lin. 3. In Mus. Westermann. 
Habitat in Java. Wied. Illustr. Gen. Achias. 
Wiedemann, Auss. Zweifl. Ins. vol. ii. p. 560. No. 4. tab. 10*. f. 4. 
Levis, juxta scutellum colore flavido abdominisque parte apicali dilatatà fus- 
cescenti tincta. Ale in medio obscuré fuscescentes, basi apiceque pallidi- 
ores, subfuscescentes, in parte obscuriori pone medium alee fascia hyalina 
exstat e tribus maculis magnis composita, macula intermedia inter nervos 
3um et 4um paulld basin versus al: extensá ; inter medium et apicem ale 
fascia altera recta vix conspicua hyalina, atque juxta nervum intermedium 
transversum fascia tertia latior adsunt. Pone et subtus scapulas utrinque 
spina brevis et subobtusa adest, pone quam altera brevior et vix conspicua 
2s2 
